Process for the preparation of monocyclic ketones having more than nine ring members



Patented Feb. 19, 1929.

UNITED STATES 1,702,852 PATENTV'OFFICE.

LEOPOLD EUZIQKA, E GENEVA, SWITZERLAND, ASSIGNOR TO M. NAEF 80 -CO., OF

GENEVA, SWITZERLAND,

A COMPANY OF- SWITZERLAND.

PBOCESS FOR THE PREPARATION OF MONOCYCLIC KETNES HAVING MORE THAN NINE 'BING MEMBERS.

No Drawing. Original application filed June 9, 1925, Serial No. 36,049, and in Switzerland June 16,1924.

Divided and this application filed November 19, 1926. Serial No. 149,544.

The carbon rings hitherto known have at most nine ring members. According to the generally accepted strain theory of A. von Baeyer the idea has arisen that carbon rings having a larger number of members either cannot be prepared or also must be very unstable.

It has now been discovered, that the whole series of multi-membered cyclic ketones hav- .0 ing from ten to eighteen ring members in one ring can'be obtamed by theusual meth- From mixtures ods for. preparing ketones.

of such di-carboxylic acids as can be obtained for example in the case of certain .5 methods of preparation, as well as from natural products, mixtures of the ketones in question are produced, which, even in this form,

can be used for technical purposes. The total ketone obtained from pure di-carboxylic 2Q acids is not homogeneous but contains, be-

sides polymethylene'ketone's', admixtures of other ketones. It has further been found that the proportion of pure polymethylene ketone in this total ketone is higher'if the cerium salts of the dicarboxylic acids are employed for the ketone preparation. These salts also give in general a higher yield of total ketone than other metallic salts.

The noteworthyobservation has also been made in this connection that starting from cyclodecanone the yields of monocyclic ketone from dicarboxylic acid in general increase with an increasing number of ring members. The multi-membered ketones, contrary to what might have been expected, are more stable in the presence of acid and alkaline agents and raised temperature than the five-membered and six-membered; monocyclic ketones. J v

These new ketones have a characteristic smell, and, moreover cyclo-pentadecanone salts of tetradecane-l.l4-dicarboxylic.acid is and the adjacent ketones have the typical musk and civet smell. and can be used as substitutes for these natural products. It has 'ral musk and civet are closely related chemically to these ketones.

Example 1.

The cerium salt of tetradecane-LM-dicarboxylic acid is heated, preferably in a vacuum, and advantageously with the addition of a good conductor of heat, such as copper or also been found that the scent-carrier of natuiron turnings, up to from 300 to more than {00 0., and the distillate obtained therefrom is-worked up by fractional distillation. The

chemical reaction takes place according to the following equation:

COO

C. (at 0.3 mm.) while the semicarbazone melts at 187 C. In the mother liquor of this semicarbazone there is a mlxture of semicarbazones melting at a lower temperature which is not sharpl defined and giving upon treatment with acids a ketone mixture. For the isolation of the ketones, instead of semicarbazide other of the usual ketone reagents may be employed. Upon oxidation with chromatic acid, tridecane-1.13-dicarboxylic acid is obtained from the cyclo-pentadecanone.

E trample 2.

Tetradecane-l.l i-dicarboxylic acid is gradually heated in the presence of cerium up to above 400 C. at the close preferably in a vacuum and the resulting distillate is worked up, according to the method described in Example 1.

- Ewample 3.

From a mixture of the cerium and thorium obtained by the method described in Example 1, cyclo-pentadecanone.

I claim:

I 1. A process for the formation of monocyclic-ketones having more than nine ring members in one ring comprising heating cerium salts of polymethylene dicarboxylic acid having more than ten carbon atoms in a normal chain the carboxylic acid groups being linked to the end carbons thereof to decompose the same.

carbon atoms in a normal chain, the carbox ylic acid groups being linked'to the end carbons thereof.-

4. A process for the formation of cyclopentadecanone comprising heating a mixture of the cerium and thorium salts of tetraclecanc-Ll i-dicarboxylic acid and working up by fractional distillation the resulting dis-' tillate. I

In testimony whereof I afiix my signature.

v LEOPOLD RUZICKA. 

